However (there's always one, isn't there), is it necessary to include a failure drill in every scenario? If you are so uncomfortable with the reliability of your guns or ammo that you must practice malfunction drills in every weapon/mag, in every string, in every drill, I would rethink my ammo or weapon choice.

When you have a failure every time, you start expecting it. The "switching gears" portion of the malfunction drill is lost. A stoppage is no longer an unexpected issue that must be recognized and corrected. You know it is going to happen and expect it, the element of surprise is gone.
Perhaps after doing the drills a few times to become familiar with them, the dummy round can be eliminated in every string and inserted (or not) randomly instead.

Joat

__________________
All things being equal, fat people use more soap. (I know I am one.) High speed, low drag does not even come close to describing ME.